Species Groups Research Articles

Tracking data highlight the importance of human-induced mortality for large migratory birds at a flyway scale

Human-induced direct mortality affects huge numbers of birds each year, threatening hundreds of species worldwide. Tracking technologies can be an important tool to investigate temporal and spatial patterns of bird mortality as well as their drivers. We compiled 1704 mortality records from tracking studies across the African-Eurasian flyway for 45 species, including raptors, storks, and cranes, covering the period from 2003 to 2021. Our results show a higher frequency of human-induced causes of mortality than natural causes across taxonomic groups, geographical areas, and age classes. Moreover, we found that the frequency of human-induced mortality remained stable over the study period. From the human-induced mortality events with a known cause (n = 637), three main causes were identified: electrocution (40.5 %), illegal killing (21.7 %), and poisoning (16.3 %). Additionally, combined energy infrastructure-related mortality (i.e., electrocution, power line collision, and wind-farm collision) represented 49 % of all human-induced mortality events. Using a random forest model, the main predictors of human-induced mortality were found to be taxonomic group, geographic location (latitude and longitude), and human footprint index value at the location of mortality. Despite conservation efforts, human drivers of bird mortality in the African-Eurasian flyway do not appear to have declined over the last 15 years for the studied group of species. Results suggest that stronger conservation actions to address these threats across the flyway can reduce their impacts on species. In particular, projected future development of energy infrastructure is a representative example where application of planning, operation, and mitigation measures can enhance bird conservation.

Two new species of planktonic Caligus O.F. Müller 1785 (Copepoda: Caligidae) from Türkiye with an updated review and checklist of planktonic caligids

Two new species of caligid sea lice, Caligus izmiriensis sp. nov., and Caligus sarosensis sp. nov. are described, based on specimens collected from the zooplankton in the Gulf of Sığacık and the Gulf of Saros off the Aegean Sea coast of Türkiye. Detailed examination of the morphology of these two new species and comparisons with other closely related caligid species, especially Metacaligus yucatanensis Suárez-Morales, Kim & Escamilla, 2012, resulted in the recognition of the genus Metacaligus Thomsen 1949 as a junior synonym of Caligus O.F. Müller, 1785. Based on this proposed synonymy, all species of the genus Metacaligus are here transferred to Caligus: Metacaligus trichiuri (Krøyer, 1863), M. rufus (Wilson, 1908), and M. unguidentatus (Rangnekar & Murti, 1950) all return to their original combinations as Caligus trichiuri Krøyer, 1863, Caligus rufus Wilson, 1908, and Caligus unguidentatus Rangnekar & Murti, 1950, respectively; Metacaligus yucatanensis Suárez-Morales, Kim& Escamilla, 2012, becomes Caligus yucatanensis (Suárez-Morales, Kim & Escamilla, 2012) comb. nov.; transferring Metacaligus latus Ho & Lin, 2002 would create a secondary homonym of Caligus latus Byrnes 1987, so a replacement name is proposed as Caligus cultellus nom. nov. We recognise C. yucatanensis as a member of the C. undulatus-group. The four other species previously placed in Metacaligus form a cluster which represents a new species group, the Caligus trichiuri-group. An updated list of planktonic caligids is presented, together with keys to species of the C. undulatus-group and of the newly proposed C. trichiuri-group. The subgenus Subcaligus Heegaard, 1943 was originally proposed to accommodate Caligus (Subcaligus) bocki Heegaard, 1943, and was characterised by its unusual stylet-like sternal furca. This subgenus has not been treated as valid by subsequent authors and we here formally propose to treat Subcaligus Heegaard 1943 as a junior synonym of Caligus.

Taxonomic notes on the Zethus olmecus de Saussure, 1875 species group (Hymenoptera, Vespidae, Eumeninae), with the description of five new species

Zethus Fabricius is the largest genus within Vespidae with nearly 300 species. The genus has a central role on discussion of social evolution, once some species share behavioral features between solitary and social representatives of vespids and the genus has been recovered as phylogenetically closer to social wasps than to other Eumeninae. The Zethus olmecus species group is even more remarkable since there are observations of communal nesting behavior, a fact misused as support for the hypothesis of closer relationship to social wasps. Herein we closely investigate the taxonomy of this group of species, the first step needed for future studies to properly approach its evolution. The taxonomic approach involved examination of external morphology and male genitalia. Five new species are described for the group: Z. bolivari n. sp., Z. hermesi n. sp., Z. hexacirratus n. sp., Z. perilloi n. sp., and Z. utingensis n. sp. The unknown female of Z. peruvicus is also described. An illustrated taxonomic key is presented. Geographical distribution is expanded for Z. peruvicus, Z. pygmaeus, Z. thoracicus, and Z. toltecus. Finally, additional notes and corrections of existing literature are given.

A new bot fly species of Cuterebra (Diptera: Oestridae) from Ecuador

A new species of cuterebrine rodent bot fly, Cuterebra yanayacui sp. nov., is described from the cloud forest of Ecuador, and it is argued that the species mimics a range of aculeate hymenopterans, including euglossine orchid bees of the genera Eufriesea Cockerell and Eulaema Lepeletier and bumble bees of the subgenus Cullumanobombus Vogt. Montemyia bureni Dalmat, 1942 is proposed as a junior synonym of Cuterebra ornata Bau, 1928, syn. nov., and an updated identification key to the species of the Metacuterebra species group within Cuterebra Clark is provided. The 5’-end of the Cytochrome c oxidase subunit I gene is sequenced for the new species and compared with published Cuterebra sequences.

Molecular phylogeny and biogeography of the dwarf boas of the family Tropidophiidae (Serpentes: Alethinophidia)

Although present in the South American continent, dwarf boas (Tropidophiidae) show their greatest extant diversification in the Caribbean region, reaching their highest diversity in Cuba. Despite their remarkable species richness, phylogenetic affinities among species of Tropidophis and Trachyboa are still poorly known. Here, we provide a multi-locus phylogenetic hypothesis of the family that includes 25 of the 37 known continental and insular species, including most of its highly diverse Cuban endemic radiation (16 out of 17 species sampled). We also provide a time-calibrated tree derived from our molecular data. Our phylogenetic results indicate that the genus Tropidophis and its mainland and Cuban radiations are paraphyletic, while the Caribbean radiation forms a well-supported clade. We therefore synonymize Trachyboa with Tropidophis and provide new definitions for the species groups. Our time-calibrated tree suggests that tropidophiids originated along the northwestern Andean region of continental South America, diverging from its known sister-group genus Anilius during the late Cretaceous. The Atlantic Rainforest radiation diverged from the Andean radiation during the late Eocene. A mainland tropidophiid ancestor subsequently dispersed from northern South America to the Caribbean region in the latest Eocene. Dispersal likely took place through a near-continuous terrestrial land bridge that connected South America to the Greater Antilles during the late Eocene to early Oligocene (35–33 Ma). The existence of this land bridge, whether formed by the Aves Ridge (GAARlandia Hypothesis) or by a more southernly positioned landmass connecting the Greater Antilles and the northern Lesser Antilles Ridge (GRANoLA hypothesis), remains a topic of debate, which we address in this paper. After that main dispersal event, West Indian tropidophiids underwent over ten speciation events, rapidly colonizing the Caribbean islands. We also address the vertebral morphology of fossil and extant Tropidophiidae, with our observations challenging the current classification of several fossil taxa within crown-Tropidophiidae.

New species of Culicoides, description of female of Culicoides pseudocrescentis Tavares & Luna Dias and new record of Culicoides castillae Fox from Southeastern Brazil (Diptera: Ceratopogonidae)

A new species of Culicoides, C. andradinensis Felippe-Bauer & Santarém is described and illustrated based on female specimens from the municipality of Andradina, São Paulo state, Brazil. The new species is placed in the limai species group and compared with their related congeners. The description of females of Culicoides pseudocrescentis Tavares & Luna Dias based on specimens from Brazilian states of Espírito Santo and São Paulo is given. Culicoides castillae Fox is first recorded from Brazil. All studied specimens are deposited in the Ceratopogonidae Collection of Fundação Oswaldo Cruz, Brazil (Fiocruz/CCER).

Retracing the evolution of Pneumocystis species, with a focus on the human pathogen Pneumocystis jirovecii.

SUMMARYEvery human being is presumed to be infected by the fungus Pneumocystis jirovecii at least once in his or her lifetime. This fungus belongs to a large group of species that appear to exclusively infect mammals, with P. jirovecii being the only one known to cause disease in humans. The mystery of P. jirovecii origin and speciation is just beginning to unravel. Here, we provide a review of the major steps of P. jirovecii evolution. The Pneumocystis genus likely originated from soil or plant-associated organisms during the period of Cretaceous ~165 million years ago and successfully shifted to mammals. The transition coincided with a substantial loss of genes, many of which are related to the synthesis of nutrients that can be scavenged from hosts or cell wall components that could be targeted by the mammalian immune system. Following the transition, the Pneumocystis genus cospeciated with mammals. Each species specialized at infecting its own host. Host specialization is presumably built at least partially upon surface glycoproteins, whose protogene was acquired prior to the genus formation. P. jirovecii appeared at ~65 million years ago, overlapping with the emergence of the first primates. P. jirovecii and its sister species P. macacae, which infects macaques nowadays, may have had overlapping host ranges in the distant past. Clues from molecular clocks suggest that P. jirovecii did not cospeciate with humans. Molecular evidence suggests that Pneumocystis speciation involved chromosomal rearrangements and the mounting of genetic barriers that inhibit gene flow among species.

Description of Rhipicephalus hibericus sp. nov. (Ixodoidea: Ixodidae), a species of the Rhipicephalus sanguineus group in southwestern Europe

We describe all the life stages of Rhipicephalus hibericus n. sp., provide the types, and present molecular support for a new species of the Rhipicephalus sanguineus sensu lato group, present in southwestern Europe, that has been historically confused with Rhipicephalus turanicus Pomerantzev, 1940. A new name is proposed for this taxon because it was impossible to ascribe to types of already described species in the group, deposited for more than 100 years in natural history institutions. The males have a dorsum showing deep and coarse punctations (absent in Rhipicephalus sanguineus sensu stricto) and adanal plates with large punctations (absent in R. sanguineus s.s.); the tail of the spiracular plate is as wide as the closest festoon (half the width in R. sanguineus s.s.). Females have large punctations in dorsal fields, a wide spiracular plate, and a “V” shaped genital opening; such a combination of characters cannot be found in other species of the group. Immatures are described from specimens collected on hosts (Rodentia and Eulipotyphla). Both larvae and nymphs are markedly smaller than R. sanguineus s.s. Nymphs display long, backward-projected auriculae; larvae are almost half the size of R. sanguineus s.s. The new species can hybridize with R. sanguineus s.s. in laboratory colonies producing an unfertile F2, laying brown and dry eggs that did not hatch. Phylogenetic analysis of partial coxI gene sequences placed R. hibericus in a well-supported clade with other sequences of R. sanguineus s.l. from Portugal, as a sister clade of R. sanguineus s.s. The new species does not belong to the R. turanicus group of species. Both 12S and 16S partial gene sequences were not as precise in the correct phylogenetic placement of R. hibericus, in part probably due to the existence of erroneously identified sequences in GenBank©. This description, together with the previous reinstatement of Rhipicephalus secundus and Rhipicephalus rutilus, and the description of the neotypes of R. sanguineus s.s. should help researchers to adequately identify their collections. Our findings demonstrate that R. turanicus is absent in southwestern Europe. Old collections should be re-examined to provide the actual range of the new species.

New Euplocania species (Psocodea: Ptiloneuridae) from Colombia, Ecuador and Nicaragua, amendments and addition to species groups

Three new species of Euplocania (Ptiloneuridae) are described, illustrated, and assigned to two species groups. These new species are E. coyolarensis n. sp., E. erwini n. sp. and E. siona n. sp. The species group danubiana is re-diagnosed, by establishing that the male hypandrium is of one sclerite, rather than three, as it had been previously diagnosed. Among the amendments proposed, the species group zelayensis now includes only E. zelayensis García Aldrete and exclude E. reyesi García Aldrete, González Obando & Carrejo and E. guentherbuchi González Obando, García Aldrete & Carrejo, as had been previously established. Species group guentherbuchi is diagnosed and includes E. guentherbuchi and E. nasa González-Obando, García Aldrete & Carrejo. Euplocania coyolarensis n. sp., is described from Nicaragua, and includes as part of the species group danubiana. Species group D is also re-diagnosed and named group erwini, including the other two species described here.

NEW SPECIES OF THE GENUS CARPELIMUS LEACH, 1819 FROM INDIA (COLEOPTERA: STAPHILINIDAE: OXYTELINAE)

A new species Carpelimus (Trogophloeus) mumbaiensis sp. n. is described and illustrated from India. The new species belongs to the ‘notumus’ species group, which is recorded for India for the first time. By the punctation of the head and elytra, weakly developed depressions on the pronotal disc, the new species is most similar to C. irianensis Gildenkov, 2020 from New Guinea. Reliably differs from it and all species of the ‘notumus’ species group in the structure of the aedeagus.

REVIEW OF LEAF BEETLES OF THE SUBGENUS HYPERICIA BEDEL, 1899 (COLEOPTERA: CHRYSOMELIDAE: CHRYSOLINA) FROM EAST ASIA

The East Palaearctic group of species in the subgenus Hypericia Bedel, 1899 (genus Chrysolina Motschulsky, 1860) is reviewed. Chrysolina (H.) nikkoensis (Jacoby, 1885) is first recorded for Kurile Islands and the Russian fauna, its type specimens studied and redescription is provided. Chrysolina (Hypericia) changbaishana sp. n. is described from Jilin Province of China; it differs from Ch. (H.) difficilis (Motschulsky, 1860) by smaller size, last abdominal ventrite without depression and narrow lateral calli of pronotum.

Revision of the ‘Acanthephyra purpurea’ species complex (Crustacea: Decapoda), with an emphasis on species diversification in the Atlantic

We inventoried all nine species of the ‘Acanthephyra purpurea’ complex, one of the most abundant and cosmopolitan group of mesopelagic shrimps. We used 119 specimens at hand and genetic data for 124 specimens from GenBank and BOLD. Phylogenetic analysis of four genes (COI, 16S, NaK, and enolase) showed that the ‘Acanthephyra purpurea’ complex is polyphyletic and encompasses two species groups, ‘A. purpurea’ (mostly Atlantic) and ‘A. smithi’ (Indo-West Pacific). The ‘A. purpurea’ species group consists of two major molecular clades A. pelagica and A. kingsleyi – A. purpurea - A. quadrispinosa. Molecular data suggest that hitherto accepted species A. acanthitelsonis, A. pelagica, and A. sica should be considered as synonyms. The Atlantic is inhabited by at least two cryptic genetic lineages of A. pelagica and A. quadrispinosa. Morphological analyses of qualitative and quantitative (900 measurements) characters resulted in a tabular key to species and in a finding of four evolutionary traits. Atlantic species showed various scenarios of diversification visible on mitochondrial gene level, nuclear gene level, and morphological level. We recorded and discussed similar phylogeographic trends in diversification and in distribution of genetic lineages within two different clades: A. pelagica and A. kingsleyi – A. purpurea - A. quadrispinosa.

Deep learning-based detection of indicator species for monitoring biodiversity in semi-natural grasslands

Deep learning (DL) has huge potential to provide valuable insights into biodiversity changes in species-rich agricultural ecosystems such as semi-natural grasslands, helping to prioritize and plan conservation efforts. However, DL has been underexplored in grassland conservation efforts, hindered by data scarcity, intricate ecosystem interactions, and limited economic incentives. Here, we developed a DL-based object-detection model to identify indicator species, a group of vascular plant species that serve as surrogates for biodiversity assessment in High Nature Value (HNV) grasslands. We selected indicator species Armeria maritima, Campanula patula, Cirsium oleraceum, and Daucus carota. To overcome the hurdle of limited data, we grew indicator plants under controlled greenhouse conditions, generating a sufficient dataset for DL model training. The model was initially trained on this greenhouse dataset. Then, smaller datasets derived from an experimental grassland plot and natural grasslands were added to the training to facilitate the transition from greenhouse to field conditions. Our optimized model achieved remarkable average precision (AP) on test datasets, with 98.6 AP50 on greenhouse data, 98.2 AP50 on experimental grassland data, and 96.5 AP50 on semi-natural grassland data. Our findings highlight the innovative application of greenhouse-grown specimens for the in-situ identification of plants, bolstering biodiversity monitoring in grassland ecosystems. Furthermore, the study illuminates the promising role of DL techniques in conservation programs, particularly as a monitoring tool to support result-based agri-environment schemes.

Evolutionary history shapes variation of wood density of tree species across the world

The effect of evolutionary history on wood density variation may play an important role in shaping variation in wood density, but this has largely not been tested. Using a comprehensive global dataset including 27,297 measurements of wood density from 2621 tree species worldwide, we test the hypothesis that the legacy of evolutionary history plays an important role in driving the variation of wood density among tree species. We assessed phylogenetic signal in different taxonomic (e.g., angiosperms and gymnosperms) and ecological (e.g., tropical, temperate, and boreal) groups of tree species, explored the biogeographical and phylogenetic patterns of wood density, and quantified the relative importance of current environmental factors (e.g., climatic and soil variables) and evolutionary history (i.e., phylogenetic relatedness among species and lineages) in driving global wood density variation. We found that wood density displayed a significant phylogenetic signal. Wood density differed among different biomes and climatic zones, with higher mean values of wood density in relatively drier regions (highest in subtropical desert). Our study revealed that at a global scale, for angiosperms and gymnosperms combined, phylogeny and species (representing the variance explained by taxonomy and not direct explained by long-term evolution process) explained 84.3% and 7.7% of total wood density variation, respectively, whereas current environment explained 2.7% of total wood density variation when phylogeny and species were taken into account. When angiosperms and gymnosperms were considered separately, the three proportions of explained variation are, respectively, 84.2%, 7.5% and 6.7% for angiosperms, and 45.7%, 21.3% and 18.6% for gymnosperms. Our study shows that evolutionary history outpaced current environmental factors in shaping global variation in wood density.

Trechus (Coleoptera: Carabidae) of Appalachia: A Phylogenetic Insight into the History of High Elevation Leaf Litter Communities

Elevation gradients provide a wealth of habitats for a wide variety of organisms. The southern Appalachian Mountains in eastern United States are known for their high biodiversity and rates of endemism in arthropods, including in high-elevation leaf-litter taxa that are often found nowhere else on earth. Trechus Clairville (Coleoptera: Carabidae) is a genus of litter inhabitants with a near-global distribution and over 50 Appalachian species. These span two subgenera, Trechus s. str. and Microtrechus Jeannel, largely restricted to north and south of the Asheville basin, respectively. Understanding the diversification of these 3–5 mm flightless beetles through geological time can provide insights into how the litter-arthropod community has responded to historical environments, and how they may react to current and future climate change. We identified beetles morphologically and sequenced six genes to reconstruct a phylogeny of the Appalachian Trechus. We confirmed the Asheville Basin as a biogeographical barrier with a split between the north and south occurring towards the end of the Pliocene. Finer scale biogeography, including mountain-range occupancy, was not a reliable indication of relatedness, with group ranges overlapping and many instances of species-, species group-, and subgeneric sympatry. This may be because of the recent divergence between modern species and species groups. Extensive taxonomic revision of the group is required for Trechus to be useful as a bioindicator, but their high population density and speciose nature make them worth additional time and resources.

A tale of two species: Disaggregating mixed historical catches of two most common skates in the Northeast Pacific Ocean

Historical catch data represent a key source of information for fisheries stock assessment models. Historically, commercial fishery catch statistics were estimated from the portion of catch landed in ports. However, many species with relatively low economic value have not been recorded on a species basis but instead as a part of an aggregate category. Reconstructing component species catch from an aggregate category is a common challenge for fisheries stock assessment efforts around the world. Skates are one group of species with low economic value for which landed catch has not been commonly reported by species. In this paper, we present a novel approach to disaggregate the historical catch of the two most abundant skate species on the West Coast of the United States, longnose skate (Caliraja rhina) and big skate (Beringraja binoculata), landed within the aggregated skate category, in ports of Washington State. We used a combination of fishery-dependent and fishery-independent data sources to account for changes in the spatial extent of the fishery over time, and differences in the depth distribution of these two skate species. While developed to disentangle aggregate catch of longnose and big skates, the approach is not limited to skates on the West Coast of the United States, but can be adapted for any species which landings have been reported within an aggregated category elsewhere.

A New Species of Diacyclops (Copepoda, Cyclopoida) from the D. crassicaudis (Sars, 1863) Species Group with Critical Taxonomy Remarks

A new species, Diacyclops dyabdar sp. nov. from the Diacyclops crassicaudis (Sars, 1863) species group from northern Middle Siberia, is described. This species is interesting from an ecological point of view, as it lives mainly in watercourses. It is well-distinguished from other species of the group by the presence of spinules on the first segments of the third and fourth pairs of swimming legs, details of the ornamentation on the fourth pair of legs and caudal rami. A detailed comparison of the new species and D. crassicaudis is presented. Molecular markers, including cytochrome c oxidase (COI) of mtDNA and 18S rRNA, ITS1 and ITS2 of nuclear DNA were obtained for a single female of D. dyabdar sp. nov. A morphometric analysis of species and subspecies of the D. crassicaudis group was carried out. It showed slight differences between the described subspecies and some species. On this basis, the subspecies D. crassicaudis, as well as D. iranicus Pesce & Maggi, 1982 and D. fontinalis Naidenow, 1969, are synonymized with the subspecies type. A more precise diagnosis of the D. crassicaudis group is indicated. This group now includes six species. The taxonomic position of several questionable taxa of Diacyclops Kiefer, 1927 described from Iran is discussed: D. landei Mahoon & Zia, 1985; D. bicuspidatus jurenei Najam-un-Nisa, Mahoon & Irfan Khan, 1987; D. landei richardi Parveen, Mahoon & Saleem, 1988 and D. jurenei Parveen, Mahoon & Saleem, 1988. These taxa are accepted as nomen dubium.

Integrative taxonomy supports two new species of Macrobiotus (Tardigrada: Eutardigrada: Macrobiotidae) allowing further discussion on the genus phylogeny

In this study, I describe two new species of Macrobiotus based on morphological data collected through light and scanning electron microscopy. Both species are accompanied by DNA sequences from four commonly used molecular markers (18S rDNA, 28S rDNA, ITS-2, and COI). Macrobiotus ovovittatus sp. nov. was discovered in Greenland and can be distinguished from similar taxa of Macrobiotus by its continuous, solid, and clearly wrinkled egg surface, adorned with sparse, very small and irregularly spaced pores. Additionally, the terminal discs of egg processes are covered in multiple light-refracting dots, resembling crocheted napkins. Macrobiotus mileri sp. nov. was found in Israel and is characterized by unique pore arrangements in its body cuticle, expressed in two distinct animal forms: (i) forma porata with large pores arranged in five distinct patches and (ii) forma aporata with single, almost undetectable pores. It also features weakly defined convex terminal discs with smooth edges. Furthermore, the phylogenetic analyses conducted in this study offer the most updated phylogeny of superclade I within the family Macrobiotidae. This facilitates additional discussion concerning the interrelationships among species within the genus Macrobiotus and the circumscription of species groups within it.

Characterization of the complete mitochondrial genome of Desmaulus extinctorium (Littorinimorpha, Calyptraeoidea, Calyptraeidae) and molecular phylogeny of Littorinimorpha.

For the purpose of determining the placement of Calyptraeidae within the Littorinimorpha, we hereby furnish a thorough analysis of the mitochondrial genome (mitogenome) sequence of Desmaulus extinctorium. This mitogenome spans 16,605 base pairs and encompasses the entire set of 37 genes, including 13 PCGs, 22 tRNAs and two rRNAs, with an evident AT bias. Notably, tRNASer1 and tRNASer2 lack dihydrouracil (DHU) arms, resulting in an inability to form a secondary structure. Similarly, tRNAAla lacks a TΨC arm, rendering it incapable of forming a secondary structure. In contrast, the remaining tRNAs demonstrate a characteristic secondary structure reminiscent of a cloverleaf. A comparison with ancestral gastropods reveals distinct differences in three gene clusters (or genes), encompassing 15 tRNAs and eight PCGs. Notably, inversions and translocations represent the major types of rearrangements observed in D. extinctorium. Phylogenetic analysis demonstrates robust support for a monophyletic grouping of all Littorinimorpha species, with D. extinctorium representing a distinct Calyptraeoidea clade. In summary, this investigation provides the first complete mitochondrial dataset for a species of the Calyptraeidae, thus providing novel insights into the phylogenetic relationships within the Littorinimorpha.

Long-term changes in qualitative composition of the Buzuluk Pine Forest avifauna (Orenburg Province area) based on retrospective and present-time observations

We conducted a comparative analysis of qualitative composition of the Buzuluk Pine Forest avifauna, mainly based on data collected by ornithologist E.P. Knorre for the period 1928–1941, and modern observations done between 2000 and the present. Retrospective data were obtained from the now-defunct Buzuluk Bor Reserve with an area of 10 503 hectares (now Borovoye-Opytnoe Forestry in the Orenburg Province). Present-time personal avifaunistic observations (using standard methods with referring to literature sources) were carried out on an area of 49 000 hectares, both in Borovoye-Opytnoe and in several adjacent forestries that were part of the Buzuluk Bor National Park within the Orenburg Province. Comparing the historical and current bird lists, we used a relative assessment of changes in the composition of various bird groups based on the observed and expected frequencies according to the χ2 test. Long-term data on average annual temperatures and precipitation from a nearby state weather station were also used. As a result, it is shown that by now the list of birds of E.P. Knorre decreased from 153 to 109 species (28.8%). When comparing by orders, the water birds were found to be the most affected group. The number of species in orders Podicipediformes, Ciconiiformes, Gruiformes decreased by 80–100%, and it dropped by more than 50% in orders Anseriformes and Charadriiformes. There was also a slightly smaller decrease in the number of species in orders Falconiformes and Strigiformes – by about 40%. An assessment of the relative changes in various bird groups from Knorre’s list based on expected and observed frequencies showed significant differences in the portion of avifauna associated with water. It decreased between 23.5% and 9% in the group ‘Limnophiles’ (χ2 = 11.7, df = 1, p = 0.0006) and between 24.8% and 9% in the group of orders represented by waterfowl and waterbird species (χ2 = 13.4, df = 1, p = 0.0002). The change in the portion of birds of prey was statistically non-significant. The same portion assessment method did not statistically confirm the decrease in the rest ecological and order groups. Comparison of groups by occurrence status found no significant changes in the portions of all groups of birds in the past and present, but the largest reduction was recorded in the group of migrating species. The portion of migrants decreased from 8.7% to 3.0% (χ2 = 3.2, df = 1, p = 0.07, Yates corrected χ2 = 2.2, p = 0.1). A dramatic decline in group of bird species associated with wetlands was suggested to be due, among other factors, to the progressive desiccation of the Buzuluk Pine Forest, as E. Knorre himself wrote in his report. The ongoing aridization of the climate, as shown by the graph of average annual air temperatures, has been taking place since at least the 20s of the twentieth century and led to the drying-up of wetlands, and also to migration of groundwater to deeper horizons. The emerging trend towards a reduction in the portion of migrants could be explained by the fact that a number of migratory bird species, mainly ducks and waders, disappeared in the study area, and several other migrants began breeding species. In addition, large-scale fires and logging led to formation of burned wasteland areas inside the forest at the beginning of the twentieth century and also probably contributed to fragmentation and desiccation of this biome.